Showing 2 results for Yazd.
H. Azimzadeh, F. Fotoohi, M. R. Ekhtesasi,
Volume 18, Issue 68 (9-2014)
Abstract
Soil surface roughness (SSR) is one of the important factors in wind and water erosion studies and control. Several parameters such as surface rock fragments influence SSR. Main objectives of this paper are to study and compare (Allmarass) random roughness (RR) and tortuosity (Tb) indices in coarse, medium and fine grain plains of Yazd-Ardakan and investigate the relationship between indices and desert pavement coverage. Roughness data were obtained by pin roghness-meter and roller chain in the three mentioned plains. RR and Tb were measured in 90cm transect length with systematic sampling pattern after determining the boundary of three kinds of plains. In each plain, 30 transects were randomly sampled and the height of soil surface roughness fractions was recorded. Distance of pins in the applied roughness meter is about 2cm. Therefore, in each 90 cm transect the height of 46 points was measured. Desert pavement coverage was measured in 20×20cm2 plots. The result showed that desert pavement coverage in coarse, medium and fine grain plains were in the range of 55-100, 40-85 and less than 5%, respectively. The relationship between RR and desert pavement was significant. The result of ANOVA (Duncan) showed, RR and Tb were significantly different in coarse, medium and fine grain plains (p-value<0.01). In addition, by increasing desert pavement percentage RR and Tb increased exponentially in base of Neper number. The relation between RR and desert pavement coverage is stronger than Tb and desert pavement coverage. Correlation between the two measured indices was calculated and compared in different plains. The result revealed that about 54, 33 and 14% of the arability in Tb could be explained by RR in coarse and medium grain plains, respectively. The correlations of two indices were significant in coarse and medium plain and insignificant in fine grain plain. The trend of RR and Tb decreased from mountain to plain center. Although RR increased slightly in fine grain plain, the difference was not significant.
D. Khosraviani, A. R. Davoudian Dehkordi, J. Givi, M. Sheibi,
Volume 19, Issue 74 (1-2016)
Abstract
The concentrations of rare-earth elements (REEs) were determined with the aim of investigating the behavior of these elements in granitic rock, granitic soils and soils between rock and lichen in Shir-kuh of Yazd province. Rare earth element patterns of the P-rich granite were determined by the mixture of Eu-enriched feldspars, middle REEs to heavy REEs-enriched apatite and Light REEs-enriched monazite. Granite-normalized REEs patterns for soils and soil lichen-granite interface represented the same signatures and similar to parent rocks. The REEs levels of the soils lichen-granite interface were similar to the concentrations of the elements in the natural compositions (Upper Continental Crust and Post-Archean Australian Shale). PAAS-normalized Rare earth element patterns for three soils’ lichen-granite interface were identical to each other and PAAS and close to the reference axis (PAAS). The same signatures of REEs in granitic rock, granitic soils and soils lichen-granite interface in arid and semi-arid mountainous areas indicate that the elements are immobile and therefore, they can be used as a suitable tracer in soil provenance studies.
